With the popularity of services like presence/IM, IMS services, push mail, push-to-talk services etc., the need for “always on” services is becoming important for service providers in telecommunication networks. For instance, the presence service may be regarded as a client-server-based home environment service, wherein the home environment (presence server) manages the presence information of users' devices (clients), services and service media, even when roaming. The presence information is a set of attributes characterizing current properties of presence information of a user's device, and it may be delivered to other user devices within the communication group. There are also plans to implement the presence feature in mobile VoIP (Voice over IP) applications, whereby it could be easily detected whether a user device can be contacted via a VoIP connection.
Instant Messaging (IM), especially in mobile environment, is a presence enabled real-time messaging service, which allows faster and quicker messaging e.g. compared to SMS text messages. Some IM applications also allow group communication. Push e-mail, in turn, is an “always-on” service, wherein new e-mail is instantly and actively transferred (“pushed”) to the e-mail client, when the e-mail arrives at the mail server.
What is common to these and many other “always-on” services is that they occasionally, but still constantly, send and receive small application-related messages. The messages are e.g. state updates, update request, keep-alive messages, or small user data messages. Typically, each service application has its own message pattern, i.e. a message transmission schedule, and the message patterns of different applications may vary significantly from each other.
However, in terms of radio resource optimisation and especially power usage in WCDMA access network, such promiscuity in message transmission is problematic. Transmission of each message requires its own radio channel activation causing extra power consumption. Furthermore, when the size of the message exceeds a threshold value, the message is always transmitted on the dedicated transport channel (DCH) of the WCDMA network, which is very power demanding compared to the rather small size of a typical message. Thus, there exists a need for a more optimised message pattern for “always-on” applications.